Pvd target with end of service life detection capability

ABSTRACT

A PVD target structure for use in physical vapor deposition. The PVD target structure includes a consumable slab of source material and one or more detectors for indicating when the slab of source material is approaching or has been reduced to a given quantity representing a service lifetime endpoint of the target structure.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/720,390, filed Sep. 26, 2005, and U.S. Provisional Application No.60/728,724, filed Oct. 20, 2005, the entire disclosures of which areincorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to physical vapor deposition (PVD). Moreparticularly, the invention relates to PVD targets.

BACKGROUND OF THE INVENTION

Physical vapor deposition (PVD) is a well known process for depositing athin film of material on a substrate and is commonly used in thefabrication of semiconductor devices. The PVD process is carried out athigh vacuum in a chamber containing a substrate (e.g., wafer) and asolid source or slab of the material to be deposited on the substrate,i.e., a PVD target. In the PVD process, the PVD target is physicallyconverted from a solid into a vapor. The vapor of the target material istransported from the PVD target to the substrate where it is condensedon the substrate as a thin film.

There are many methods for accomplishing PVD including evaporation,e-beam evaporation, plasma spray deposition, and sputtering. Presently,sputtering is the most frequently used method for accomplishing PVD.During sputtering, a gas plasma is created in the chamber and directedto the PVD target. The plasma physically dislodges or erodes (sputters)atoms or molecules from the reaction surface of the PVD target into avapor of the target material, as a result of collision with high-energyparticles (ions) of the plasma. The vapor of sputtered atoms ormolecules of the target material is transported to the substrate througha region of reduced pressure and condenses on the substrate, forming thethin film of the target material.

PVD targets have finite service lifetimes. PVD target overuse, i.e., usebeyond the PVD target's service lifetime, raises reliability and safetyconcerns. For example, PVD target overuse can result in perforation ofthe PVD target and system arcing. This, in turn, may result insignificant production losses, PVD system or tool damage and safetyproblems.

The service lifetime of a PVD target is presently determined by trackingthe accumulated energy, e.g., the number of kilowatt-hours (kw-hrs),consumed by the PVD system or processing tool. The accumulated energymethod, however, takes time to master and the accuracy of this methoddepends solely on the hands-on experience of the technician. Even whenmastered, the service lifetimes of the PVD targets are still less thanthey could be, as approximately 20-40 percent of the PVD target(depending upon the PVD target type) is wasted. This problem is depictedin FIG. 1, which is a graph plotting the erosion profile of aconventional PVD target comprising a consumable slab of source material.As can be seen, approximately 60 percent of the original quantity of thePVD target (target residue) remained after 1769 accumulated kw-hrs ofoperation of the PVD process system.

The low target utilization resulting from the PVD targets' abbreviatedservice lifetimes, creates high PVD target consumption costs. In fact,PVD target consumption cost is one of the most significant costs insemiconductor fabrication. Thus, if much of the wasted target materialcould be utilized, PVD target consumption costs could be substantiallyreduced. This, in turn, would significantly lower semiconductorfabrication costs and increase profitability.

The low target utilization also results in more frequent replacement ofthe PVD target and, therefore, more frequent maintenance of the PVDsystem or tool. Further, when the PVD target is replaced, time is neededto retune the PVD process for the new target.

Accordingly, there is a need for an improved PVD target.

SUMMARY

One embodiment is a slab of consumable material such as a PVD target foruse in physical vapor deposition. The slab of consumable materialcomprises at least one detector for signaling that the slab isapproaching or has been reduced to a predetermined quantity ofconsumable material.

In one exemplary embodiment, the detector comprises an enclosure atleast partially embedded within the slab of consumable material and afilament or electrode elements disposed within the enclosure. In anotherexemplary embodiment, the enclosure is evacuated to create a vacuuminside the enclosure. In another exemplary embodiment, the filament orelectrode elements extend from within the enclosure to enable connectionto a signal monitoring device. In still another exemplary embodiment,the enclosure is composed of the consumable material.

In another exemplary embodiment, the at least one detector comprises anenclosure at least partially embedded within the slab of consumablematerial and one of a gas, a liquid, and a solid disposed within theenclosure.

In a further exemplary embodiment, the at least one detector comprises alayer of material comprising a composition different from the slab ofconsumable material, the layer of material disposed adjacent the slab ofconsumable material, the layer of material being detectable when atleast partially vaporized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1, which is graph plotting the erosion profile of a conventionalPVD target structure comprising a slab of source material.

FIG. 2A is a base plan view illustrating an exemplary embodiment of aPVD target structure.

FIG. 2B is a cross-sectional view through line 2B-2B of FIG. 2A.

FIG. 3 is a cross-sectional view through illustrating another exemplaryembodiment of a PVD target structure.

FIG. 4 is a cross-sectional view illustrating a further exemplaryembodiment of a PVD target structure.

FIG. 5 is an exemplary embodiment of a system for detecting the servicelifetime endpoint of a PVD target structure.

FIG. 6 is another exemplary embodiment of a system for detecting theservice lifetime endpoint of a PVD target structure.

FIGS. 7A and 7B are base plan views of PVD targets having pluraltube-based detectors.

FIGS. 8A and 8B are cross-sectional views showing two exemplarylocations where the tube may be embedded in the base surface of thetarget.

FIG. 8C is a cross-sectional view illustrating an exemplary method forembedding the tube shown in the location depicted in FIG. 8A.

FIG. 8D is an elevational view illustrating the thin foil depicted inFIG. 8C.

FIGS. 9A-9F are perspective views showing various exemplary embodimentsof the tube of the tube-based detectors.

FIG. 10 is perspective view showing the removal of a mandrel-like moldmember from a tube during the manufacture of same.

FIGS. 11A and 11B are perspective views showing an exemplary method formanufacturing the tubes of the tube-based detectors in bulk.

FIGS. 12A, 12B, 13A and 13B are perspective view showing the tubes ofthe tube-based detectors manufactured using an exemplary sheet formingmethod.

FIG. 14 is a perspective view illustrating yet another exemplaryembodiment of a PVD target structure.

FIG. 15 is a perspective view illustrating still another exemplaryembodiment of a PVD target structure.

FIG. 16 shows a table which lists some exemplary detector layermaterials that are suitable for use with some exemplary targetmaterials.

FIG. 17A is a flowchart showing the steps of a first exemplaryembodiment of a tube making method.

FIG. 17B is a flowchart showing the steps of a second exemplaryembodiment of the tube making method.

FIG. 18A is a perspective view of an exemplary embodiment of amold/extrusion-die apparatus, which may be used in the tube makingmethod.

FIG. 18B is a perspective view of another exemplary embodiment of a moldapparatus, which may be used in the tube making method

FIG. 19 is a flowchart showing the steps of a third exemplary embodimentof the tube making method.

FIG. 20 is a flowchart showing the steps of a fourth exemplaryembodiment of the tube making method.

DETAILED DESCRIPTION

One embodiment is a physical vapor deposition (PVD) target structurehaving a service lifetime endpoint detector. FIG. 2A is a plan viewillustrating an exemplary embodiment of a PVD target structure of theinvention, denoted by numeral 100 and FIG. 2B is a cross-sectional viewthrough line 2B-2B of FIG. 2A. The PVD target structure 100 comprises aconsumable slab 110 of a desired source material (PVD target) and afilament detector 120, embedded in a base surface 114 of the PVD target110.

The PVD target 110 comprises a reaction surface 112, the base surface114 opposite the reaction surface 112, and a sidewall surface 116extending between the reaction surface 112 with the base surface 114.The target 110 may be formed in any suitable and appropriate shapeincluding, for example, circular, square, rectangular, oval, triangular,irregular, etc. The target 110 may be formed using any well known PVDtarget forming method. See for example U.S. Pat. No. 6,858,102 entitled“Copper-Containing Sputtering Targets, And Methods Of FormingCopper-Containing Sputtering Targets.”

The target 110, in one embodiment, may have a diameter (in the case of acircular target) of 18 inches and a thickness of 0.250 inches. In otherembodiments, the target 110 may be formed to other suitable andappropriate dimensions. The target 110 may be composed of any suitableand appropriate source material including, for example, nickel (Ni),nickel platinum (Ni Pt) alloys, nickel titanium (Ni Ti) alloys, cobalt(Co), aluminum (Al), copper (Cu), titanium (Ti), tantalum (Ta), tungsten(W), indium tin oxide (ITO), zinc sulfide-silicon dioxide (ZnS—SiO₂),gold (Au), silver (Ag) and other noble metals.

The filament detector 120 comprises an enclosure formed by a tube 122having opposing open ends 122 a, 122 b which are closed by isolators 126a, 126 b. The isolators 126 a, 126 b hermitically seal the interior 122c of the tube 122 and suspend a filament 124 within the interior 122 cof the tube 122. In one embodiment, the air within the interior 122 c ofthe tube 122 may be evacuated therefrom to create a vacuum therein. Inan alternative embodiment, the interior 122 c of the tube 122 may befilled with an inert gas.

The filament 124 includes bent marginal end portions 124 a, 124 b whichextend through the isolators 126 a, 126 b. The isolators 126 a, 126 belectrically isolated the bent marginal end portions 124 a, 124 b of thefilament 124 from the tube 122 and the PVD target 110. The bent marginalend portions 124 a, 124 b of the filament 124 terminate externally toform filament terminals or leads 125 a, 125 b. The filament leads 125 a,125 b allow connection of the filament 124 to a monitoring instrument,as will be described further on.

In one exemplary embodiment, the tube 122 may be composed of the samematerial as the PVD target 110. The diameter of the tube 122 should besufficiently small and its location sufficiently close to the basesurface 114 so that it is not penetrated until nearly all the targetmaterial 110 has been used. For example, in one exemplary embodiment,the tube 122 may have a diameter of about 0.5 mm.

The filament 124 is typically composed of the same material as the PVDtarget 110. In an alternative embodiment, the filament 124 may becomposed of a material which is different from the material of thetarget 110 and does not affect the PVD processing result. The filamentmay have a diameter of about 0.2 mm in one exemplary embodiment.

The isolators 126 a, 126 b are made from an electrically isolatingmaterial or combination of materials. In one exemplary embodiment, theisolators 126 a, 126 b may be composed of a ceramic, such as alumina(Al₂O₃).

The filament detector 120 functions as a sensor for indicating when thePVD target 110 has been reduced to a quantity of material representing aservice lifetime endpoint of the target 100 structure. Any usage of thePVD target structure 100 beyond this quantity (PVD target overuse) willlikely result in perforation of the target 110 and system arcing, whichin turn, may result in production loss, PVD system or tool damage andsafety problems. The use of the filament detector 120 in the PVD targetstructure 100 maximizes the service lifetime of the target 110 andallows accurate, automated detection of when the PVD target structure100 should be replaced to prevent the target related problems mentionedabove.

The filament detector 120 is constructed to exhibit a characteristic orattribute that can be in-situ monitored by a monitoring device 330 (FIG.5) connected to the filament 124 of the filament detector 120. In oneembodiment, the characteristic or attribute of the filament 124 to bemonitored may be the electrical resistance or impedance of the filament124 and the monitoring device 330 may be an ohmmeter. Using the examplewhere the characteristic or attribute is the electrical resistance orimpedance of the filament 124, at the beginning of the PVD targetstructure's service lifetime in a PVD process chamber, the electricalresistance or impedance monitored by the monitoring device 330 will besome initial value. As the PVD target 110 erodes during PVD processing,the electrical resistance or impedance will remain at the initial valueuntil the tube 122 is breached to expose the filament 124 suspended inthe tube 122 to the PVD process, thus allowing the plasma (in the caseof sputtering) to contact and erode the filament 124. When this occurs,the electrical resistance or impedance will change from the initialvalue, thereby indicating that the PVD target structure 100 isapproaching the end of its useful life. At this point, the quantity ofthe target 110 remaining may be some predetermined percentage of theoriginal quantity of the target 110. For example, in one embodiment, thequantity of the target 110 remaining when the filament 124 is firstexposed may be approximately 0.5 percent of the original quantity of thetarget 110. As the target is further used in the PVD process chamber,the target 110 and the filament 124 will continue to be eroded until thefilament 124 fractures. When this occurs, the electrical resistance orimpedance will change again because the filament 124 becomes an opencircuit, thereby indicating that the PVD target structure 100 hasreached the end of its service lifetime. Using the previous example, thequantity of the target 110 remaining when the filament 124 fractures maybe approximately 0.2 to 0.1 percent of the original quantity of thetarget 110. In response to the second change in electrical resistance orimpedance, the operation of the PVD process system or tool may be haltedmanually by a technician, or halted automatically by a signal sent fromthe monitoring device 330 to the PVD process system or tool (or acontroller that operates the tool).

Referring now to FIG. 3, there is shown a cross-sectional viewillustrating another exemplary embodiment of a PVD target structure,denoted by numeral 100′. The PVD target structure 100′ comprises theearlier described consumable target 110 (composed of a desired sourcematerial) and an electrode detector 120′, embedded in the base surface114 of the target 110. The electrode detector 120′ is similar to thefilament detector 120 of the previous embodiment, except that thefilament 124 is replaced by two separate, opposing electrodes 124 a′,124 b′. The electrodes 124 a′, 124 b′ include bent marginal end portions124 aa, 124 bb which extend through the isolators 126 a, 126 b. The bentfilament portions 124 aa, 124 bb terminate externally to form filamentleads 125 a′, 125 b′. The filament leads 125 a′, 125 b′ allow attachmentof the electrodes 124 a′ 124 b′ to the earlier described monitoringdevice 330 (FIG. 5).

In operation, the electrodes 124 a′, 124 b′ of the electrode detector120′ will detect a current generated by ions in the plasma entering thetube 122 when the tube 122 of the detector 120′ is breached. In thisembodiment, the monitoring device or instrument connected to theelectrodes 124 a′, 124 b′ may be a current measuring device orinstrument.

FIG. 4 is a cross-sectional view illustrating another embodiment of thePVD target structure, denoted by numeral 200. The PVD target structure200 comprises a PVD target 210 composed of a desired source material, asin the previous embodiments, and an inert gas detector 220 embedded inthe base surface 214 of the target 210.

The inert gas detector 220 comprises a tube 222 having opposing openends 222 a, 222 b. The tube 222 may be similar or identical to the tubedescribed in the embodiment shown in FIGS. 2A and 2B. The open ends 222a, 222 b of the tube 222 are closed and hermetically sealed by closures226, such as plugs made from the same material as the tube 222 or anyother suitable material. The tube 222 is filled with an inert gas 224,such as helium (He), which does not affect the PVD processing result.

During PVD processing, the target 200 is in-situ monitored for emissionof the inert gas 224 by a gas detection device 430 (FIG. 6). As the PVDtarget 210 erodes during PVD processing, the inert gas 224 remainsundisturbed in the tube 222, until the tube 222 is breached by PVDprocess forces, e.g., the sputtering plasma. Once this occurs, the inertgas 224 filling the tube 222 is emitted and may be detected by the gasdetection device 420. The gas detection device 430 may be by opticalemission spectroscopy (OES), residual gas analysis (RGA), or othersuitable detection method. In one exemplary embodiment, the inert gasdetector 220 allows the target 210 of the PVD target structure 200 to bereduced to a quantity less than 0.5 percent of its original quantity.

Thus, the inert gas detector 220 operates as a sensor to indicate whenthe target 210 of target structure 200 has been reduced to a quantityrepresenting a service lifetime endpoint of the target structure 200.

In another exemplary embodiment, the inert gas filling the tube 222 ofthe gas detector 220 may be replaced by another substance that does notaffect the PVD processing result. The substance may be a solid or aliquid that is capable of evaporating when exposed to the PVD process,to enable detection of the substance thereafter. The solid substance maybe powered material listed in the “coated material” column of the tableshown in FIG. 16 which lists some exemplary materials that will noteffect the PVD processing result of respective exemplary targetmaterials listed in the “target material” column of the FIG. 16 table.The liquid substance may be an inert gas (e.g., helium) in liquid formthat may be injected into the tube. When filled with a liquid substance,the tube may have a diameter as small as 0.03 mm.

The PVD target structures 100, 100′, 200 described above comprise asingle tube-based detector 120, 120′ 220. In other exemplaryembodiments, the target structure may comprise multiple tube-baseddetectors distributed across the PVD target, preferably in the moreerosive positions of the target (e.g., FIG. 7A). Distributing multipletube-based detectors across the target increases detection uniformityand allows detection of localized target erosion. FIGS. 7A and 7B,illustrate two exemplary embodiments of a PVD target structure 500, 500′comprising two or more, tube-based detectors 520, 520′ (each having, forexample, a length of 4 cm or less) distributed across the base surface514, 514′ of the PVD target 510, 510′ and embedded therein. As shown inFIG. 7A, the tube-based detectors 520 may be distributed radially acrossthe target slab 510 and separate from one another. As shown in FIG. 7B,the tube-based detectors 520′ may be distributed radially across thetarget 510′ and such that they converge with one another at the centerof the target 510′.

In some exemplary embodiments, the tube-based detectors 620 may beembedded in the base surface 614 of the PVD target 610 so that the tube622 is flush with or slightly recessed from the base surface 614 of thetarget 610 (as well as the target base plate 650, which may be made of acopper (Cu) alloy, such as Cu—Zn or any other suitable material), asshown in FIG. 8A. This may be accomplished in one embodiment, as shownin FIG. 8C, by forming the PVD target 610 as a source material member610.1 made of the desired source material (e.g., tantalum) and aninterface member 610.2 made of an interface material (e.g., titanium).The abutting surfaces of the source material and interface members 610.1and 610.2 may be provided with corresponding tube receiving grooves611.1 and 611.2 which are sized and shaped to receive a portion of thetube 622. The tube 622 is placed in the tube receiving grooves 611.1 and611.2 and the source material and interface target members 610.1 and610.2, the tube 622 and the target base plate 650 are bonded to oneanother using a hot press bonding process performed at a pressure andtemperature sufficient to cause the source material and interfacemembers 610.1 and 610.2, the tube 622 and the target base plate 650 tophysically bond to one another. Specifically, the pressure andtemperature depends upon the material of the base plate, the sourcematerial of the target, and the bonding time. In the example used above(e.g., copper base plate and tantalum source material), the temperatureand pressure used may be about 400° C. (slightly over ⅓ of the meltingtemperature of copper which is 1083° C.) and about 13,000 psi,respectively. In some embodiments, a thin foil 610.3 made of the sourcematerial may be disposed in the tube receiving groove 611.2 of theinterface member 610.2. The foil 610.3, shown by itself in FIG. 8D, maybe used as a barrier layer to prevent atoms of the interface member610.2 from migrating into the area of the groove 611.2 of the tube 622and the source material 610.1. In other embodiments, the tube-baseddetectors 620′ may be at least partially embedded in the base surface614′ of the target 610′ so that the top of the tube 622′ is slightlyabove the base surface 614′ of the target 610, as shown in FIG. 8B. Thetarget base plate 650′ in this embodiment may include a recess 660 forreceiving the portion of the tube 622 that protrudes from the basesurface 614′ of the target 610′, so that the base surface 614′ of thetarget 610 may lie flush on the target base plate 650′.

The tube(s) of the tube-based detectors may be constructed in anysuitable and appropriate shape. The tube may have outer and innersurfaces that have identical or different cross-sectional shapes. FIGS.9A-9F are perspective views showing some exemplary embodiments of thetubes. FIG. 9A show a tube 700 a having outer and inner surfaces 710 a,720 a with circular cross-sectional shapes. FIG. 9B shows a tube 700 bhaving outer and inner surfaces 710 b, 720 b with diamondcross-sectional shapes. FIG. 9C shows a tube 700 c having an outersurface 710 c with a square cross-sectional shape and an inner surface720 c with a circular cross-sectional shape. FIG. 9D shows a tube 700 dhaving an outer surface 710 d with a circular cross-sectional shape andan inner surface 720 d with a triangular cross-sectional shape. FIG. 9Eshow a tube 700 e having an outer surface 710 e with a circularcross-sectional shape and an inner surface 720 e with a squarecross-sectional shape. FIG. 9F shows a tube 700 f having outer and innersurfaces 710 f, 720 f with square cross-sectional shapes. The outer andinner surfaces of the tube(s) may have other cross-sectional shapesincluding rectangular and oval, to name a few.

Referring now to FIG. 14, there is shown a perspective view illustratingyet another exemplary embodiment of a PVD target structure, denoted bynumeral 800. The PVD target structure 800 comprises the above describedconsumable PVD target 810 (composed of a desired source material) and adetector layer 820, disposed adjacent the base surface 814 of the target810. In the embodiment of FIG. 14, the detector layer 820 may couple thePVD target structure 800 to a base plate 850.

FIG. 15 shows a perspective view illustrating still another exemplaryembodiment of a PVD target structure, denoted by numeral 800′. The PVDtarget structure 800 is similar to the PVD target structure embodied inFIG. 14 except that it additionally comprises a target material layer830 disposed over the detector layer 820. In the embodiment of FIG. 15,the target material layer 830 couples the PVD target structure 800′ tothe base plate 850.

In the embodiments of FIGS. 14 and 15, the detector layer 820 iscomposed of a material, which is different from the PVD target materialand does not affect the PVD processing result. FIG. 16 shows a tablewhich lists some exemplary detector layer materials that are suitablefor use with respective exemplary target materials.

When plasma strikes the detector layer 820 of the PVD target structure800 or 800′ during PVD processing, the detector layer emits a vaporwhich may be in-situ monitored and detected by OES, RGA or other likedetection methods.

The endpoint detection resolution of the PVD target structures 800 and800′ may be increased, by using two or more detector layers which arecomposed of different materials. Thus, when plasma strikes the first oneof the detector layers, detection of that layer will indicate a firstresidual quantity of target material remaining and when plasmasubsequently strikes a subsequent one of the detector layers, detectionof that layer will indicate a subsequent residual quantity of targetmaterial remaining, which is less than the previous residual quantity.Additional layers of other materials may be added, if desired, toprovide an indication of an additional residual quantity of material.

The PVD target structures may be configured and adapted to be used withor without a target base plate. PVD processing systems and tools may usethe PVD target structures without significant hardware modificationsand/or changes. Further, the PVD target structures may be used indifferent magnetic PVD systems including magnetron systems, capacitivelycoupled plasma (CCP) systems, and inductively coupled plasma (ICP)systems, to name a few. The PVD target of the invention may also be usedin all types of PVD power supply systems including, without limitation,direct current power systems, alternating current power systems, andradio frequency power systems.

Another embodiment is a method for making the tube(s) of the tube-basedtarget structures. FIG. 17A presents a flowchart that shows the steps ofa first exemplary embodiment of the tube making method. In step 901, amold/extrusion-die apparatus 950 (FIG. 18A) is provided which comprisesconcentrically disposed outer and inner die members 951, 952. The outerand inner die members 951, 952 are each made of a rigid materialsuitable for extruding and/or casting metal, metal alloys, and/ormetallic materials. Suitable die member materials may include, withoutlimitation, ceramic materials, polymeric materials, metallic materials,and combinations thereof. The inner surface 95 a of the outer member 951of the apparatus 950 is configured to form the outer surface of the tubeand the outer surface 952 a of the inner member 952 of the apparatus 950is configured to form the inner surface of the tube. In the embodimentof FIG. 18A, the outer member 951 of the apparatus 950 is configuredwith a circular cross-sectional shape and the inner member 952 of theapparatus 950 is configured with a circular cross-sectional shape. Sucha mold/extrusion-die apparatus may be used to make the tube shown inFIG. 9A. It is contemplated, however, that the outer and inner members951 and 952 of the apparatus 950 may be configured to make a PVD targettube of any desired shape including, for example, the tubes shown inFIGS. 9B-9F.

Referring again to the flowchart of FIG. 17A, step 902 of the methodcomprises extruding a desired tube material through the space 953defined between the outer and inner members 951, 952 of themold/extrusion-die apparatus 950. Extrusion may be performed using coldor hot extrusion methods. In an alternate embodiment, step 902 of themethod comprises casting the desired tube material into the space 953defined between the outer and inner members 951, 952 of themolding/extrusion die apparatus 950. Casting may be performed by meltingthe desired tube material and pouring or injecting the molten tubematerial into the space 953 defined between the outer and inner members951, 952 of the apparatus 950. If the tube material is formed by castingin step 902, then step 903 is performed wherein the tube is removed fromthe apparatus 950 after the molten tube material has cooled andsolidified.

FIG. 17B presents a flowchart that shows the steps of a second exemplaryembodiment of the tube making method of the invention. In step 911 amold apparatus 960 (FIG. 18B) is provided which comprises a mandrel-likemold member 961. The mold member 961 is made of a rigid materialsuitable for forming thereon a layer of metal, metal alloy, and/ormetallic material, using PVD or electrical chemical plating. Suitablemold member materials may include, without limitation, ceramicmaterials, polymeric materials, metallic materials, and combinationsthereof. The mold member 961 of the apparatus 960 has an outer surface961 a which is configured to form a tube having outer and inner surfacesof substantially the same shape. In the shown embodiment of FIG. 18B,the outer surface 961 a of the mold member 961 is configured with acircular cross-sectional shape. Such a mold apparatus may be used tomake the tube shown in FIG. 9A. It is contemplated, however, that themold member 961 of the mold apparatus 960 may be configured to make aPVD target tube of other desired shapes including, for example, thetubes shown in FIGS. 9B and 9F.

Referring again to the flowchart of FIG. 17B, step 912 of the methodinvolves depositing a desired tube material onto the outer side surface962 of the mold member 961, until a desired film thickness (wallthickness of the tube) is achieved. The depositing step may be performedusing, for example, electrical chemical plating (ECP) and/or PVDmethods. In step 913, the mandrel-like mold member 961 and the tube areseparated from one another. In an exemplary embodiment, the separationstep may be performed by physically withdrawing the mandrel-like moldmember from the tube, as shown in FIG. 10. In an alternative exemplaryembodiment, the separation step may be performed chemically by the moldmember using an etchant.

FIG. 19 presents a flowchart that shows the steps of a third exemplaryembodiment of the tube making method. In the third exemplary embodimentof the tube making method, the tube is made in a bulk manufacturingprocess. In step 921, multiple bores 941 are formed in a bulk quantityof a desired tube material 940 as shown in FIG. 11A. The multiple bores941 define the inner surfaces of a plurality of tubes. In step 922, thebulk quantity of material is cut or sliced into a plurality of discretetubes 942 as shown in FIG. 11B, each of the tubes 942 comprising one ofthe bores 941. The bores 941 may be formed using conventional laser,high-pressure water, wet etching, and dry etching methods. The bulkmaterial 940 may be cut or sliced into the plurality of discrete tubesusing conventional laser, high-pressure water, and mechanical cuttingmethods.

FIG. 20 is a flowchart that shows the steps of a fourth exemplaryembodiment of the tube making method. In step 931, a sheet 980, 980′ ofthe desired tube material is provided, and in step 932, the sheet 980 isformed into a tube 981, 981′ of a desired shape, as shown in FIGS. 12Aand 13A. The sheet 980, 980′ may be formed into the desired tube shapein step 932 by forming it around a correspondingly shaped mandrelsimilar to that shown in FIG. 18B. The matching, opposing edges 982,982′ of the tube 981, 981′ are then bonded to one another in step 933 tocomplete the tube 981, 981′ as shown in FIGS. 12B and 13B. Bonding maybe accomplished using any suitable and appropriate bonding method, suchas welding.

Another embodiment of the invention is a system for detecting theservice lifetime endpoint of a PVD target structure. FIG. 5 is anembodiment of such a system, denoted by numeral 300. The system 300comprises a PVD process chamber 310, a PVD target structure 320 such asshown in FIGS. 2A, 2B or 3, disposed in the process chamber 310 and amonitoring device 330 connected to the PVD target structure 320 forin-situ monitoring the characteristic or attribute of the filament orelectrode detector assembly 340 of the PVD target structure 320.

FIG. 6 is another embodiment of a system for detecting the servicelifetime endpoint of a PVD target, denoted by numeral 400. The system400 comprises a PVD process chamber 410, a PVD target structure 420,such as shown in FIGS. 4, 14, or 15, disposed in the process chamber 410and a gas detection device 430 for in-situ monitoring and detecting theinert gas detector or detector layer 440 of the PVD target structure420.

Although the invention has been described in terms of exemplaryembodiments, it is not limited thereto. Rather, the appended claimsshould be construed broadly, to include other variants and embodimentsof the invention, which may be made by those skilled in the art withoutdeparting from the scope and range of equivalents of the invention.

1. A slab of consumable material comprising at least one detector forsignaling that the slab of consumable material is approaching or hasbeen reduced to a predetermined quantity of the consumable material. 2.The slab of consumable material of claim 1 wherein the slab ofconsumable material comprises a physical vapor deposition target.
 3. Theslab of consumable material according to claim 1, wherein the at leastone detector comprises: an enclosure at least partially embedded withinthe slab of consumable material; and one of a filament element andelectrode elements, disposed within the enclosure.
 4. The slab ofconsumable material according to claim 3, wherein the enclosure isevacuated to create a vacuum inside the enclosure.
 5. The slab ofconsumable material according to claim 4, wherein the one of thefilament element and the electrode elements extend from within theenclosure to enable connection to a signal monitoring device.
 6. Theslab of consumable material according to claim 3, wherein the enclosureis composed of the consumable material.
 7. The slab of consumablematerial according to claim 3, wherein the one of the filament elementand the electrode elements is composed of the consumable material. 8.The slab of consumable material according to claim 3, wherein the one ofthe filament element and the electrode elements is composed of an inertmaterial that does not affect the vapor deposition process.
 9. The slabof consumable material according to claim 1, wherein the at least onedetector comprises: an enclosure at least partially embedded within theslab of consumable material; and one of a gas, a liquid, and a soliddisposed within the enclosure.
 10. The slab of consumable materialaccording to claim 9, wherein the one of the gas, the liquid, and thesolid is capable being detected when released from the enclosure. 11.The slab of consumable material according to claim 10, wherein detectionof the one of the gas, the liquid, and the solid indicates that aremaining quantity of consumable material of the slab is approaching orat the predetermined quantity.
 12. The slab of consumable materialaccording to claim 1, wherein the at least one detector comprises: alayer of a second material comprising a composition different from theconsumable material, the layer of the second material disposed adjacentthe slab of consumable material, the layer of the second material beingdetectable when vaporized.
 13. The slab of consumable material accordingto claim 12, wherein detection of the vaporized layer of the secondmaterial indicates that the quantity of the slab of consumable materialis approaching or at the predetermined quantity.
 14. The slab ofconsumable material according to claim 12, wherein the layer of thesecond material is disposed between the slab of consumable material andan additional layer of the consumable material.
 15. The slab ofconsumable material of claim 1 wherein the signaling indicates an end oflife of the slab of consumable material.
 16. The slab of consumablematerial of claim 9 wherein the slab of consumable material comprises atarget for use in a physical vapor deposition process, the one of thegas, the liquid, and the solid being of a composition that does notaffect the vapor deposition process.
 17. The slab of consumable materialof claim 11 wherein the slab of consumable material comprises a targetfor use in a physical vapor deposition process, and the composition ofthe layer of the second material does not affect the vapor depositionprocess.
 18. A slab of consumable material comprising a plurality ofdetectors for signaling that the slab of consumable material isapproaching or has been reduced to a predetermined quantity ofconsumable material.
 19. A physical vapor deposition target comprising:a slab of consumable material; and at least one detector for signalingthat the slab of consumable material is approaching or has been reducedto a predetermined quantity of consumable material.
 20. The physicalvapor deposition target of claim 19, wherein the at least one detectorincludes one of a filament, opposing electrodes, a detection layer, agas, a liquid, and a solid that produces the signaling.